* Themes.c: each system now tries to obtain a system specific icon from the
theme (i.e. icon/new_os4.info). If that fails YAM will fall back to the
normal unspecific icon (i.e. icon/new.info). This makes it possible to
distribute system specific icons like the new big icons from AmigaOS4.1
update 1 with a theme without forcing users of other systems without on-the-
fly icon scaling to use these big icons.

- added support for creating the debugging archives as well. So now YAM is compiled twice for every platform
- fixed the release archive creating process in many ways and added DEVFLAGS= support
- renamed the "distribution" makefile target to "release" so that "make release" can be entered.

* Makefile: added "distribution" target. This one creates the distribution archives for
AmigaOS3, AmigaOS4 and MorphOS. The YAM binaries and required libraries/classes are
*NOT* yet copied!!
Before anybody complains: YES, I know, the current approach is quite ugly...

* misc: reverted the changes of revision 4473 where Thore forced all
NListview objects to always carry a vertical scrollbar no matter what.
While this fixed the graphics corruption symptoms reported lately,
it does not seem to be a wise decision to work around this issue in
YAM when the root of the problem is known to be originating from NList.
We really need to fix that in NList later, so to allow YAM to benefit
from further NList improvements it is better not to force YAM to
use vertical scrollers at all times.

* mui/Searchwindow.c: performing a next search in the read window now just
removes a notification instead of erasing the parent window pointer. First,
this makes it possible to let the "not found" window to reference the
correct parent window, and second it fixes bug #2921931 as a NULL pointer
was used without check before.

* misc: all NListview objects are now forced to get a vertical scrollbars
attached, no matter if it is required at all or configured otherwise in the
NListview settings. This is meant to work around certain layout issues with
dynamically added scrollbars.

* YAM.c, YAM_US.c: a directory passed to YAM via the MAILDIR command line
option or ToolType will now be reused upon a restart to make sure that the
same directory is used everytime. Additionally the first and main user's
mail directory can now be changed from within YAM. Please note however that
using MAILDIR is not recommended with multiple users as all users will share
the same configuration and mails, which most probably might not be what you
really intended. All in all this fixes bug #2923953, where different
directories (one configured but up to now unchangeable, another passed via
MAILDIR) for the main user resulted in a default configuration upon a
restart.

* YAM_AB.c, YAM_MA.c, ReadWindow.c, WriteWindow.c: all toolbars are now placed
into a scrollable virtual group where they really belong as subclasses of
TheBarVirt.mcc. This makes it possible to resize the corresponding windows
smaller than the toolbar's size. This partly fixes bug #2925005.

* YAM_AB.c: YAM will now accept numbers greater or equal to 1900 for %y year
placeholders, even if the standard allows two digits only. However, please
note that YAM will convert any year number back to two digits if the locale
formatting string contains a %y instead of %Y and hence may produce non
unique date strings. Sorry, but if your locale country file still contains
such ancient placeholders it is really time to upgrade or to live with the
consequences. Especially OS3 will at some point suffer from this. This
finally fixes bug #2923855.